{"overview":"The Mamiya RB67 37mm f\/4.5 Fisheye is an ultra-wide fisheye lens for the Mamiya RB67 medium format SLR system, providing a circular or near-circular image projection on the 6x7 frame. Designed for architectural, landscape and creative work where extreme angle of view is required, it pairs with the RB67's bellows focusing body and leaf-shutter mount.","market_narrative":"Hammer prices for the 37mm Fisheye are scarce at saleroom level, with one verified UK auction result at £688 in January 2024 setting the only firm reference point we have today in 2026. With so little turnover, that figure should be read as a single data point rather than a true median, and clean, fungus-free copies with the original hood and caps can plausibly sell for more when they do appear. Buyers asking what a Mamiya RB67 37mm Fisheye is worth should weigh condition heavily, since cosmetic and optical faults move the value sharply.","buying_guide":"Inspect the deeply curved front element for cleaning marks, coating scratches and edge chips, and look through the lens for fungus or haze, both common in older medium format glass stored in humid conditions. Check the leaf shutter and aperture blades for oil contamination and confirm shutter speeds fire cleanly across the range, then work the focus helicoid for smooth, even travel without stiffness or grease migration. Finally, check for any sign of element separation or balsam discolouration, and confirm that the rear mount, locking pin and shutter cocking mechanism all engage correctly with the RB67 body.","specs":"Specifications on file are limited to the headline data: a 37mm focal length at f\/4.5 maximum aperture, fisheye projection, in the Mamiya RB67 bayonet mount with built-in leaf shutter typical of the RB67 Sekor line.","faq":[{"q":"What is a Mamiya RB67 37mm f\/4.5 Fisheye worth at UK auction?","a":"The single verified UK hammer result on file is £688 from January 2024, so that price is the best available benchmark for what one sells for, though thin sales data means individual results can vary widely with condition."},{"q":"How much does a Mamiya RB67 37mm Fisheye sell for compared to standard RB67 lenses?","a":"Specialist fisheye optics like the 37mm typically command a clear premium over standard 90mm or 127mm RB67 Sekor lenses because production volumes were much lower, and the £688 reference price reflects that scarcity."},{"q":"Is the RB67 37mm Fisheye a good value buy today?","a":"For RB67 users who specifically need a fisheye field of view, it is the native option and retains value well; for general shooting the price and specialist projection make it a deliberate purchase rather than an everyday lens."},{"q":"What should I check before buying one?","a":"Prioritise the front element coating, internal haze and fungus, smooth focus, and a clean leaf shutter free of oil on the aperture blades, since these are the faults that most affect both usability and resale price."}],"confidence":35,"reasoning":"Only one verified sales record is available and SPECS\/facts are empty, so pricing commentary and specifications are necessarily thin."}